How do properly managed sewage treatment plants affect surface water quality?

Properly managed sewage treatment plants play a crucial role in enhancing surface water quality by treating domestic wastewater before it is discharged into rivers, lakes, and other water bodies. The treatment process typically involves several stages—primary, secondary, and sometimes tertiary treatment—that remove harmful contaminants and pollutants from the wastewater. This process helps to reduce the levels of nutrients, pathogens, and organic matter that could otherwise degrade water quality and harm aquatic ecosystems.

When sewage treatment plants adequately process wastewater, they minimize the risks of eutrophication (caused by excess nutrients) and the spread of waterborne diseases, which can occur if untreated or poorly treated wastewater is released. Thus, by ensuring that wastewater is effectively treated to remove pollutants before entering surface waters, these plants contribute significantly to maintaining healthier aquatic environments and improving overall surface water quality.